IRedMail/FAQ/Ignore.Trash.Folder.in.Quota

Quota_rule is overrode in /etc/dovecot/dovecot-mysql.conf or /etc/dovecot/dovecot-ldap.conf, so please change them instead. If no per-user quota rules found, Dovecot will use 'quota_ruleX' in dovecot.conf.

For example, with OpenLDAP backend, you have /etc/dovecot/dovecot-ldap.conf, update it with 'Trash:ignore' like below: